If you tell your GP that you are planning on trying for a baby soon then you can get a prescription for Pregaday which is an iron and folic acid supplement. The doc should give you enough for 3 months worth if you're lucky. It is recommended that you take pre-natal vitamins for 3 months before trying to conceive because it gets your body ready for pregnancy and can significantly reduce the risk of neural tube defects in the baby.
Have you been using any hormonal contraception? If so, you might want to stop taking that now and use a barrier method such as the cap or condoms because your fertility can be affected by certain hormonal contraception. The depo is notorious for it and Implanon also.
Don't drink very much, don't smoke and don't take recreational drugs. Basically, like Katrina said, treat your body as if you're already growing a baby!
Good luck!
(PS I'm copying this to the Getting Pregnant forum where you may get more replies

)